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251 Flathead heads question


Dansk

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My 151 Chrysler had the original flathead 6 swapped at some point to a 251 IND 8 industrial engine. It runs well so no problem but the head on the IND engine lacks the "Spitfire" script which I think is cool. I located a Desoto in a junkyard that has the script on the head. I don't know the displacement but it is a 25" motor. I'm no expert for sure but my understanding is that the script only started in 1951 with the 251 displacement engine.  My question is if there could be any compatability issue if I spring for the $75 that the junkyard wants for that head with the idea of replacing the one I have?

Edited by Dansk
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OK this might work but figure you will have to have the head milled to make it perfectly level and flat also new head gasket taking the old head off the car with a potential to break a head bolt.

 

So figure all of this into the equation just to have a cool looking head as to compared to your engine running fine right now with no know issues and any thing that also break when trying to make the engine look COOL.

 

Purchase the head to have a spare but see my last comment.

 

I come from the way of thinking: IF IT IS NOT BROKE THAN LEAVE IT ALONE BECAUSE YOU ALWASY WILL BREAK SOMETHING.

 

Rich Hartung

Edited by desoto1939
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My first series 1949 (same as 1948) has Spitfire cast in the head and is the original engine. If your block is a 25 inch there should be no problem with the swap. You may want to replace the water distribution tube in the head.

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New head gasket. New Thermostat housing gasket. Little water neck 90 gasket. Drain and save coolant for reuse. 
Break a head bolt. Damage mechanical temperature gauge bulb upon removal.  Ether is now gone. DOA. Next, you end up getting in there and testing valve seat seal-ability. New Intake manifold gaskets. New Exhaust manifold gaskets. New Carb mounting gaskets. Then the valve lap ensues. Followed by a complete carb disassembly and ultrasonic soak. Full new carb kit and reassembly. 
 

But hey, that’s just what happens to me when I try to upgrade to the cooler looking “Spitfire Head”. 

 

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Thanks for the reply's. I'm very new to these engines and I'm glad everyone pointed out that it isn't just buy a gasket and bolt it on. I had no idea and don't even know what a water distribution tube is so plenty to learn

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2 hours ago, desoto1939 said:

OK this might work but figure you will have to have the head milled to make it perfectly level and flat also new head gasket taking the old head off the car with a potential to break a head bolt.

 

So figure all of this into the equation just to have a cool looking head as to compared to your engine running fine right now with no know issues and any thing that also break when trying to make the engine look COOL.

 

Purchase the head to have a spare but see my last comment.

 

I come from the way of thinking: IF IT IS NOT BROKE THAN LEAVE IT ALONE BECAUSE YOU ALWASY WILL BREAK SOMETHING.

 

Rich Hartung

That’s my normal take also.  But considering that higher compression is the best/easiest/fastest way to more HP.  I’d be tempted to  mill the Spitfire, a lot, and make the swap 

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15 hours ago, kencombs said:

That’s my normal take also.  But considering that higher compression is the best/easiest/fastest way to more HP.  I’d be tempted to  mill the Spitfire, a lot, and make the swap 


I just researched this. The 251 25” head combustion chamber holds 100 ml of oil. The 218 (Canadian) 25” head holds 85 ml of oil. 15% smaller. The  218 head is going on the 251 engine this week! 15% more compression? Not quite. 15% more heat to disperse? Likely. 

 

FYI the waterpump comes off to check water distribution tube. 

Edited by keithb7
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The Spitfire name in the head of Chrysler engines goes back at least to 1941 and it was used up to the early 50s I think.  It was a left over nickname from the WWII era.  My first car was a 50 Chrysler Windsor with the Spitfire engine.  Spitfire was painted red, but I'm told it didn't come from the factory that way.  

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Dansk,

Marc is right the Spitfire goes back to 1941. Sniper is right no distribution tube in the head. If you want that head you better snag it especially for $75.

They ain't easy to come by for that price. As far as possible warp, just check it with a straight edge and feeler gauge. P-B Blaster will be your best friend too.

Literally marinate the bolts and Temp Gauge Gland Nut before dis-assembly. Use a new Head Gasket. Wala you da man. Otherwise if everything is running smooth just clean up the head you bought and put it on the shelf. Besides if you get sick of looking at it you can always sell it on ebay for a profit. If you like turning wrenches its a good excercise for you.

Good Luck

Tom

Edited by Tom Skinner
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